Download Chapter 3.3 How Introduced Species Affect Ecosystems

Chapter 3.3
How Introduced Species Affect Ecosystems
Road map for today
 Go over and mark WB pages 46-49
Warm up game
Native vs. non-native
species
 Invasive species and
their impacts (4)
 Workbook pages
52-55
What’s happening here?
Warm-up game:
Name That (Invasive) Species
Warm-up game:
Name That (Invasive) Species
Warm-up game:
Name That (Invasive) Species
“A public health hazard, hogweed's clear, watery
sap has toxins that cause photo-dermatitis. Skin
contact followed by exposure to sunlight
produces painful, burning blisters that may
develop into purplish or blackened scars.”
-Noxious weeds, King County, Washington
http://www.kingcounty.gov/environment/animalsAndPlants/noxious-weeds/weedidentification/giant-hogweed.aspx
Warm-up game:
Name That (Invasive) Species
Warm-up game:
Name That (Invasive) Species
Video
http://www.youtube.com/watch?v=gFchSGI0jB4
Native species vs. non-native species
• Native species are plants and animals that
naturally inhabit an area
• Introduced species new species of plants and
animals introduced accidentally or on purpose
– A.K.A. foreign species, non-native species, exotic
species, or alien species
– Many of these species are harmless, or sometimes
even beneficial
– Occurred due to immigration over past 400 years
Invasive species
• Organisms that can take over the habitat of
native species or invade their bodies, thus
weakening immune system.
Invasive Species
• Often have high reproductive rates, are
aggressive competitors, and lack natural
predators in new habitats
• Have potential to dramatically change
ecosystems through
– Competition
– Predation
– Disease and parasitism
– Habitat alteration
Impacts of invasive species
• Competition: invasive species compete against
native species for essential resources such as
food and habitat
• Predation: invasive species can have more
impact on a prey population than native
predators, as prey may not have adaptations to
escape or fight them off
American Bullfrog
Impacts of invasive species
• Disease and Parasitism: can weaken the
immune response of an ecosystem’s native
plants and animals, influencing humans
• Allows opportunity for less dominant species
to outcompete other species
European Starling
outcompetes western bluebirds
for nesting habitat
Norway Rat
Eats ground-nesting
sea birds’ eggs
Impact of Invasive Species
• Habitat alteration: make a natural habitat
unsuitable for native species by changing its
structure or composition
•
•
•
•
Change light level
Decrease dissolved O2
Change soil chemistry
Increase soil erosion
• E.g., scotch broom acidifies soil
West Nile Virus
• Introduced to U.S. in 1999, started causing
deaths in birds and illness in humans in NY
• Carried by mosquito
How is this related to invasive species?
http://www.youtube.com/watch?v=EVk5rfIA4kU
Pick two
• Silent Invaders
• http://www.youtube.com/watch?v=9JQ6oHjpeq
U
• Spit
• http://www.youtube.com/watch?v=eqoT8tcZq6k
• Death Scent
• http://www.youtube.com/watch?v=8LkRChkUIR
M
Habitat alteration
• Eurasian Milfoil first ID’d in
Okanagan Lake in 1970.
• Forms wide, dense mats at
lake surfaces
• Cuts off sunlight
• Interferes with
boaters/swimmers
• Can grow from fragments
 spreads!!!
Saving an Ecosystem Under Siege
• Often requires human
intervention to save established
ecosystems
• Garry Oak Ecosystem Recovery
Team (GOERT) is trying to save
several areas because Garry Oak
trees:
– Are a Keystone Species
– May be better suited for future
than Douglas fir forests
• Scotch broom, and English ivy are
biggest threats
Garry Oak Forests
• 95% of the original ecosystem has been lost to
urban development
• The remaining 5% is threatened by invasive
species.
Cleaning up the fragments of the chapter
Native species
Non-native species
Invasive species
Impacts of invasive species (4)
 Workbook pages 52- 55
 Next class…Ch3 review!
Coming up… Ch 3 Celebration
of Learning! 